TWI559379B - Method for laser annealing semiconductor wafers with local control of ambient oxygen - Google Patents

Description

Method for laser annealing semiconductor wafers with local control of ambient oxygen

This invention relates to a laser annealing, and more particularly to a method of laser annealing with localized control of ambient oxygen.

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Laser annealing (also known as laser spike annealing, laser thermal annealing, or laser heat treatment) is used in a variety of applications in semiconductor processes, including when forming active microcircuits such as transistors and related types of semiconductor characteristics. A dopant for activating selected regions of a device (structure) formed on a semiconductor wafer.

The laser annealing process is generally carried out in a vacuum processing chamber (or a reaction chamber), such as the microchambers disclosed in U.S. Patent No. 5,997,963 and U.S. Patent No. 9,029,809. One of the reasons for using vacuum is to reduce the amount of oxygen present on the surface of the semiconductor wafer being processed because oxygen is highly reactive and oxidizes the surface of the semiconductor wafer. This is especially true at high temperatures associated with laser annealing because high temperatures accelerate the oxidation rate.

Under normal vacuum conditions, the oxygen concentration inside the processing chamber can be reduced to about 50 (ppm) (vol.). Further low oxygen concentration will be problematic and expensive equipment (eg, a more powerful vacuum pump) will be required and the processing chamber will be substantially modified.

Therefore, there is a need for a low cost and simple way to achieve a reduction in the oxygen content of the surface of a semiconductor wafer after laser annealing by a conventional vacuum based method.

One concept of the present invention is a method of laser annealing a semiconductor wafer having a surface. The method includes: disposing a semiconductor inside a processing chamber; evacuating an interior of the processing chamber such that oxygen contained in the processing chamber is at an initial oxygen concentration; and introducing a mixed gas into the processing chamber, wherein the mixed gas includes Hydrogen and buffer gas; and directing the laser beam through the interior of the processing chamber to be incident on an annealing site on the surface of the semiconductor wafer, thereby annealing the surface of the semiconductor wafer and causing oxygen in a localized region around the annealing site The hydrogen in the mixed gas is locally heated, and oxygen and hydrogen in a local region are combusted to generate water vapor, so that the oxygen concentration in the local region is lower than the initial oxygen concentration.

In another concept of the above method of the present invention, the mixed gas preferably contains 5 vol% of hydrogen and 95 vol% of nitrogen.

In another method of the above-described concept of the present invention, the localized region is preferably defined by a combustion temperature T _C, where T _C is the temperature of combustion in the range between 100 ^o C to 500 ^o C it.

In another concept of the above method of the invention, the processing chamber preferably comprises a microchamber.

In another concept of the above method of the present invention, the method preferably further comprises moving the semiconductor wafer relative to the laser beam to move the laser annealing position relative to the surface of the semiconductor wafer, but the annealing position is relative to Its initial position inside the processing chamber remains fixed.

In another concept of the above method of the present invention, the initial oxygen concentration is preferably 50 ppm or more. The oxygen concentration in the localized region is preferably 10 ppm or less.

In another concept of the above method of the invention, the semiconductor wafer preferably has a melting temperature T _M . The surface of the semiconductor wafer is preferably annealed at an annealing temperature T _A , where T _A &lt; T _M .

Another concept of the present invention is a method of reducing oxygen in a localized region around an annealing location when a semiconductor wafer having a surface is subjected to laser annealing. The method includes introducing a mixed gas comprising hydrogen and a buffer gas into a processing chamber, wherein the processing chamber comprises a semiconductor wafer and oxygen at an initial concentration; and a surface of the laser-annealed semiconductor wafer, thereby causing the annealing location to be located The oxygen in the partial region and the hydrogen in the mixed gas are locally heated, and the oxygen and hydrogen in the local region are burned to generate water vapor, so that the oxygen concentration in the local region is lower than the initial oxygen concentration.

In another concept of the above method of the present invention, the mixed gas preferably contains 5 vol% of hydrogen and 95 vol% of nitrogen.

In another method of the above-described concept of the present invention, the localized region is preferably defined by a combustion temperature T _C, where T _C is the temperature of combustion in the range between 100 ^o C to 500 ^o C it.

In another concept of the above method of the invention, the processing chamber preferably comprises a microchamber.

In another concept of the above method of the invention, the processing chamber preferably has a pressure below atmospheric pressure.

In another concept of the above method of the present invention, the method preferably further comprises moving the semiconductor wafer relative to the laser beam to move the annealing position relative to the surface of the semiconductor wafer, but the annealing position is relative to The initial position of the interior of the processing chamber remains fixed.

In another concept of the above method of the present invention, the initial oxygen concentration is preferably 50 ppm or more. The oxygen concentration in the localized region is preferably 10 ppm or less.

In another concept of the above method of the invention, the semiconductor wafer preferably has a melting temperature T _M . The surface of the semiconductor wafer is annealed at an annealing temperature T _A , where T _A &lt; T _M .

Another concept of the invention is a method of laser annealing a semiconductor wafer having a surface. The method includes: disposing a semiconductor wafer inside a processing chamber, wherein the inside of the processing chamber contains oxygen at an initial oxygen concentration; introducing a mixed gas into the processing chamber, wherein the mixed gas comprises hydrogen and a buffer gas; and guiding the lightning The beam passes through the interior of the processing chamber to be incident on an annealing site on the surface of the semiconductor wafer, thereby annealing the surface of the semiconductor wafer and causing local heating of oxygen in the partial region around the annealing site and the hydrogen in the mixed gas. And the oxygen in the local region is combusted with hydrogen to generate water vapor, so that the oxygen concentration in the local region is lower than the initial oxygen concentration.

In another concept of the above method of the present invention, the method preferably further comprises vacuuming the interior of the processing chamber after the semiconductor wafer is disposed inside the processing chamber. The initial oxygen concentration is defined by a residual oxygen amount (concentration) remaining in the processing chamber after evacuation.

In another concept of the above method of the present invention, the initial oxygen concentration is preferably 50 ppm or more. The oxygen concentration in the localized region is preferably 10 ppm or less.

In another concept of the above method of the invention, the processing chamber preferably comprises a microchamber.

In another concept of the above method of the present invention, the mixed gas preferably contains 5 vol% of hydrogen and 95 vol% of nitrogen.

The technical content of the present invention is disclosed in the following examples, which are not intended to limit the present invention. Any modifications and refinements made by those skilled in the art without departing from the spirit of the present invention are intended to be included in the scope of the present invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

The invention is illustrated in detail by the various embodiments and drawings. In the drawings, the same or similar reference numerals are used to refer to the same or similar elements. The drawings are not necessarily drawn to true scale, and those of ordinary skill in the art can readily understand the drawings only to illustrate the key concepts of the invention.

The scope of the claimed patents is incorporated in and constitutes a part of this detailed description.

The disclosure of any of the published or published patent documents cited herein is incorporated by reference.

The card coordinates shown in some of the figures are for reference and are not intended to limit the orientation or orientation.

In the following description, the term "pulling a vacuum" or "evacuated", which is connected to the interior of a processing chamber, means that the pressure inside the processing chamber is lowered to be lower than the ambient pressure or atmospheric pressure outside the processing chamber. Force, and does not necessarily mean removing (emptying) all atoms from the interior of the processing chamber. The method of one embodiment disclosed herein includes evacuating or otherwise evacuating the interior of the processing chamber, wherein an initial concentration of _COX of oxygen is left within the processing chamber. In this context, the term "initial concentration" is used to mean that the local control of the oxygen content of the processing chamber is performed with this concentration as the beginning and ends with an oxygen concentration lower than the initial concentration C _OX .

In this paper, the terms "process" and "method" are interchangeable.

The term "local control of ambient oxygen" is understood to mean a partial reduction in oxygen content (concentration) compared to the initial content (concentration) of oxygen. Processing chamber system

1A is a schematic illustration of a cross-section (in the X-Z plane) of a processing chamber system (referred to as system) 10 suitable for performing one of the methods disclosed herein. Figure 1B is an exploded view of some of the major components of system 10 in Figure 1A. Fig. 1C is a plan view (in the X-Y plane) of the system 10 in Fig. 1A, with line 1-1 showing the cross section taken in Fig. 1A. Figures 1A through 1C are from the published patent No. 344 and describe a processing chamber referred to as a "microchamber."

System 10 has a Z-center line CZ along the Z direction and an X-center line CX along the X direction. System 10 is in an ambient environment 8, and ambient environment 8 may contain at least one reactive gas, such as oxygen. The surrounding environment 8 may also contain non-reactive gases such as helium, argon or a stabilizing gas such as nitrogen.

System 10 includes a top member 20 having an upper surface 22, a lower surface 24 and an outer edge 26. In an embodiment, the top member 20 is generally rectangular and has an upper surface 22 and a lower surface 24 that are parallel to each other. In an embodiment, the top member 20 is cooled, as will be described in more detail below. In an embodiment, the top member 20 includes at least one light entry feature 30 that allows at least one laser beam 40 to pass through the top member 20. In one embodiment, the at least one light entrance feature 30 includes one or more apertures, while in another embodiment, the light entrance feature 30 can include at least one window.

System 10 also includes a clamp 60 having an upper surface 62, a lower surface 64 and an outer edge 66. The clamp 60 is generally cylindrical, centered about the Z-center line CZ, and the upper surface 62 is adjacent and parallel to the lower surface 24 of the top member 20. Clamp 60 (along with centerline CZ) operates in operation of system 10, as described below. The upper surface 62 of the clamp 60 is spaced from the lower surface 24 of the top member 20 by a distance D1 wherein the distance D1 is between 50 microns and 1 mm and thus defines the interior (internal) of the process chamber having a distance D1. . In one embodiment, a semiconductor substrate (wafer) 50 upper surface 52 and a top surface 20 lower surface 24 define an interior 70 and a distance D1.

The upper surface 62 of the clamp 60 is disposed to support the wafer 50 having an upper surface 52, a lower surface 54 and an outer edge 56. In one embodiment, wafer 50 is a single wafer. Wafer 50 may be a wafer product that has been processed to fabricate a semiconductor device and is being further processed by laser beam 40. In the top view of FIG. 1C, wafer 50 is represented by a dashed circle. In one embodiment, the jig 60 is heated, and, in a further embodiment of the embodiment, the jig 60 is provided to the wafer 50 is heated above about 400 ° C to a wafer temperature T _W. In one embodiment, at least one of the laser beams 40 includes one or more laser annealing beams, that is, one or more laser beams that can perform an annealing process on the wafer 50, such as dopant diffusion.

System 10 also includes a thermal insulation layer 80 having an upper surface 82, a lower surface 84 and an outer edge 86. The heat insulating layer 80 is disposed in close proximity to the lower surface of the jig 60 to allow the heat insulating layer 80 to exchange heat therewith. In some embodiments, the insulating layer 80 is comprised of glass, ceramic material, or gaps. In an embodiment, the upper surface 82 of the insulating layer 80 is in intimate contact with the lower surface 64 of the clamp 60.

As described below, system 10 also includes a cooling device 90 that is configured to thermally manage the heat generated by fixture 60 and the heat generated by laser beam 40 incident on wafer 50. The cooling device 90 of an embodiment includes an upper surface 92, a lower surface 94 and an outer edge 96. Cooling device 90 selectively includes a recess 98 defined by support surface 100 and inner wall 102. The recess 98 is provided to match the heat insulating layer 80 and the jig 60 such that the heat insulating layer 80 is supported by the support surface 100.

In one embodiment, the inner wall 102 of the cooling device 90, the outer edge 86 of the insulating layer 80, and the outer edge 66 of the clamp 60 define a gap G1. In a further embodiment, the cooling device 90 includes one or more gas flow passages 104 that provide a gas flow path from the support surface 100 to the lower surface 94 such that the gas 202 entering the gap G1 from the interior 70 can pass through the cooling device 90. The lower surface flows out of the interior 70. The insulating layer 80 can also be an air gap.

System 10 also includes a mobile stage 120 having an upper surface 122 and a lower surface 124. The system 10 further includes an annular member 150 disposed adjacent the outer edge 96 of the cooling device 90 and coupled to a water-cooled reflective skirt (not shown) that surrounds the clamp assembly 68 and is coupled thereto. mobile. The annular member 150 has a body 151 and includes an upper surface 152, a lower surface 154, an inner surface 155 and an outer edge 156. The combination of the clamp 60, the insulating layer 80 and the cooling device constitutes a clamp assembly 68. The combination of the clamp assembly 68, the mobile stage 120 and the annular member 150 constitutes a mobile stage assembly 128. The top member 20 is fixed relative to the mobile stage assembly 128. The mobile stage assembly 128 has an outer perimeter 129, which in one embodiment is defined in part by the outer edge 156 of the annular member 150.

The surface 122 of the mobile stage 120 supports the cooling device 90. The mobile stage 120 is operatively coupled to a positioner 126 that is configured to move the mobile stage 120 and position the mobile stage 120 as needed, and to track the position of the mobile stage 120 relative to a reference position. The mobile stage 120 is operatively supported by a platen 130 having an upper surface 132 to allow the mobile stage 120 to move in the X-Y plane.

The lower surface 20 of the top member 20, the outer edge 156 of the annular member 150 and the upper surface 132 of the platen 130 define an air curtain region 158.

In an embodiment, the mobile stage 120 and the clamp 60 are integrated into a one-piece or two-piece movable clamp that is operatively coupled to the positioner 126. The top member 20 has a sufficient length in the X direction to move the clamp 60 relative to the top member 20 so that the laser beam 40 can be exposed to the entire upper surface 52 of the wafer 50.

System 10 also includes at least one gas supply system 200 and at least one coolant supply system 250 that supplies coolant 252. In an embodiment, a first gas supply system 200 is provided to provide gas 202 to the interior 70 and another gas supply system 200 is provided to provide gas 202 to the annular member 150. In one embodiment, different gas supply systems 200 provide different gases 202, while in another embodiment, different gas supply systems 200 provide the same gas 202. The annular member 150 is arranged to control the flow of gas 202 into a peripheral gap G3 to form an air curtain (not shown). The peripheral gap G3 has a width or size W _G3 .

In another embodiment, a single gas supply system 200 is used to provide gas 202 to the interior 70 and the annular member 150. The gas 202 of an embodiment may comprise one or more inert gases such as helium, argon, helium and nitrogen. In an embodiment, the gas 202 is comprised of one or more inert gases. In another embodiment, the gas 202 comprises a selected amount of at least one reactive gas, such as oxygen. As described below, the gas 202 may comprise or consist of a mixed gas comprising hydrogen and nitrogen.

System 10 also includes a control unit 300 operatively coupled to gas supply system 200 and coolant supply system 250 and configured to control operation of gas supply system 200 and coolant supply system 250, as described in U.S. Patent No. 9,029,809. To create an air curtain. The system 10 also includes a vacuum system 260 that is coupled to the interior 70, such as via at least one airflow passage 104 that includes a gap G2 having a width W _G2 . Vacuum system 260 can be used to create a vacuum in interior 70. Local control of ambient oxygen during laser annealing

2 is a simplified diagram of system 10 in FIG. 1A showing the annealing process of an embodiment and the process of local control of ambient oxygen as disclosed herein. Figure 3A is a close-up view of a portion of the interior 70 prior to annealing of the laser beam 40 and the upper surface 52 of the wafer 50 and after introduction of the mixed gas 202 to the interior 70. The mixed gas 202 is mixed with oxygen 205 for display. FIG. 3B is a close-up view of the laser beam 40 annealing the upper surface 52 of the wafer 50 at the annealing location 55.

As described above, it is necessary to further reduce the initial concentration C _OX of the oxygen 205 in the interior 70 to further reduce the amount of oxidation that may occur on the surface 52 of the wafer 50. Although this can be accomplished throughout the interior 70, in practice only the oxygen concentration at the annealing location 55 where the laser fire occurs is reduced.

Thus, in a method of an embodiment of the invention, a gas 202 comprised of a mixture of hydrogen and an inert buffer gas, such as 5 vol% hydrogen and 95 vol% nitrogen, is supplied to the interior 70 as a mixed gas 202. The interior 70 is also evacuated through the action of the vacuum system 260, and the interior 70 contains oxygen 205 having an initial concentration C _OX (also referred to as background concentration), in one embodiment, having an initial concentration C _OX (ie, background) The concentration of oxygen 205 is as low as about 50 ppm. As shown in FIG. 3A, when the mixed gas 202 is directed into the interior 70, the mixed gas 202 rapidly spreads (diffuses) to the entire interior 70, which includes a region that is rapidly spread to the surface 52 immediately adjacent to the wafer 50, and Mix with oxygen 205.

Injection of the mixed gas 202 into the interior 70 can be accomplished via operation of the gas supply system 200 prior to or during the annealing process, wherein the laser beam 40 is moved relative to the laser beam 40 as the wafer 50 is moved by the clamp 60. It is incident and scanned across the upper surface 52 of the wafer 50 as indicated by arrow AR. In one embodiment, the partial pressure of the mixed gas 202 at the interior 70 is between about 1 millitorr and 1000 Torr. In one embodiment, the pressure within the interior 70 is less than 760 Torr, i.e., less than one atmosphere pressure.

In the annealing process of an embodiment as shown in FIG. 3B, the laser beam 40 heats the upper surface 52 of the wafer 50 to an annealing temperature T _A at an annealing position 55, and the annealing temperature T _A approaches or exceeds the melting of the wafer. Temperature T _M , for 矽, T _M =1, 414 ° C. For non-melting laser annealing, the annealing temperature T _A of the upper surface 52 of the wafer 50 is within 400 ° C of the melting temperature T _M . For melt annealing, T _A ≥ T _M . Note that when the wafer 50 is scanned (moved relative to the laser beam 40), the anneal location 55 "moves" relative to the upper surface 52 of the wafer 50, but remains fixed relative to its initial position within the interior 70. .

Heating the upper surface 52 of the wafer 50 with the laser beam 40 at the annealing location 55 is also used to locally heat the mixed gas 202 and oxygen 205 within the interior 70, particularly near the annealing location 55. The spatial variation of the mixed gas temperature T _FG within the interior 70 generally corresponds to the vicinity of the mixed gas 202 at the annealing location 55, i.e., the closer to the annealing location 55, the greater the mixed gas temperature T _FG . Here, it is noted that the content of the mixed gas 202 is greater than the content of the oxygen gas 205 (initial concentration C _OX ) such that the "gas" temperature within the interior 70 is substantially defined by the mixed gas 202.

2, 3A and 3B respectively show that the mixed gas temperature T _{FG is} associated with a combustion temperature isotherm T _{C that} locally heats the upper surface 52 of the wafer 50 at the annealing location 55. The combustion temperature isotherm T _C represents the combustion temperature at which the following combustion reaction occurs within the interior 70 of a given chamber pressure: 2H ₂ + O ₂ → 2H ₂ O _(vapor) Equation 1 The combustion temperature isotherm T _C defines a portion Region RG, which includes a portion 70 that is centrally located in the hemispherical portion of the annealing location 55. Within the local region RG, the mixed gas 202 has a mixed gas temperature T _FG ≥ T _C , thus indicating that a combustion reaction of Formula 1 occurs within a volume within the interior 70.

The combustion reaction of Formula 1 is used to reduce the concentration of oxygen 205, that is, the concentration of oxygen 205 is reduced from the initial concentration C _OX (ie, background concentration) present in the interior 70 but outside the local region RG to one of the local regions RG. Lower concentration (value) C' _OX . This is illustrated in Figure 3B, where the initial concentration C _OX of oxygen 205 outside of the localized region RG is greater than the concentration C' _OX within the localized region RG (i.e., C _OX &gt;C' _OX ).

The mixed gas 202 thus serves to locally control (reduce) the amount of oxygen 205 in the localized region RG. The control via the combustion reaction of Formula 1 occurs, which involves breaking the oxygen molecules are oxygen atom, oxygen atom and bound dihydro atom from a mixed gas of 202 to form H ₂ O (water) vapor. This local process occurs within the localized region RG and can occur during the annealing process to reduce the oxidation content of the upper surface 52 of the wafer 50. In one embodiment, the concentration C' _OX of oxygen 205 in the localized region RG is C' _OX ≤ 10 ppm.

In one embodiment, within the range of partial pressures of the interior 70, the combustion temperature is about T _C = 600 ° C as described above. It is assumed that the substantially semicircular partial region RG is generally centered at the annealing position 55, and the radius r _{G of the} local region RG may be about r _G =1 μm to 10 mm at T _C = 600 °C. The concentration of hydrogen atoms of the mixed gas 202, the diffusivity of hydrogen atoms in the interior 70, the initial concentration C _OX of the oxygen 205 in the interior 70, and the rate of the combustion reaction of Formula 1 all enable the combustion reaction of Formula 1 to be initiated. And continuing, so that the oxygen concentration in the local region RG is lower than the initial oxygen concentration or the initial concentration C _OX .

Although the technical content of the present invention has been disclosed in the above preferred embodiments, it is not intended to limit the present invention, and any modifications and refinements made by those skilled in the art without departing from the spirit of the present invention are encompassed by the present invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.

8‧‧‧ surroundings
10‧‧‧Processing chamber system (system)
20‧‧‧ top member
22‧‧‧ upper surface
24‧‧‧ lower surface
26‧‧‧ outer edge
30‧‧‧Light entrance features
40‧‧‧Laser beam
50‧‧‧Semiconductor substrate (wafer)
52‧‧‧ upper surface
54‧‧‧ lower surface
55‧‧‧Annealed position
56‧‧‧ outer edge
60‧‧‧ fixture
62‧‧‧ upper surface
64‧‧‧ lower surface
66‧‧‧ outer edge
68‧‧‧Clamp assembly
70‧‧‧Processing chamber interior (internal)
80‧‧‧Insulation layer
82‧‧‧ upper surface
84‧‧‧ lower surface
86‧‧‧ outer edge
90‧‧‧Cooling device
92‧‧‧ upper surface
94‧‧‧ lower surface
96‧‧‧ outer edge
98‧‧‧ recess
100‧‧‧Support surface
102‧‧‧ inner wall
104‧‧‧Air passage
120‧‧‧Mobile stage
122‧‧‧ upper surface
124‧‧‧ lower surface
126‧‧‧ Locator
128‧‧‧Mobile stage assembly
129‧‧‧ outer periphery
130‧‧‧ board
132‧‧‧ upper surface
150‧‧‧ ring members
151‧‧‧Ontology
152‧‧‧ upper surface
154‧‧‧ lower surface
155‧‧‧ inner surface
156‧‧‧ outer edge
158‧‧‧Air curtain area
200‧‧‧ gas supply system
202‧‧‧ gas (mixed gas)
205‧‧‧Oxygen
250‧‧‧ coolant supply system
252‧‧‧ coolant
260‧‧‧vacuum system
AR‧‧‧ arrow
CX‧‧‧ center line
CZ‧‧‧ center line
D1‧‧‧ distance
G1‧‧‧ gap
G2‧‧‧ gap
G3‧‧‧ perimeter clearance
RG‧‧‧ local area
r _G ‧‧‧ Radius
T _C ‧‧‧ combustion temperature isotherms
W _G2 ‧‧‧Width
W _G3 ‧‧‧Size

[FIG. 1A] FIG. 1A is a schematic cross-sectional view (in the X-Z plane) of a processing chamber system suitable for performing a local control method of laser annealing and ambient oxygen according to an embodiment of the present invention. [Fig. 1B] is an exploded view of some of the main components of the processing chamber system of Fig. 1A. [Fig. 1C] is a plan view (in the X-Y plane) of the processing chamber system in Fig. 1A, the line 1-1 of which shows the cross section taken in Fig. 1A. [Fig. 2] is a simplified diagram of the processing chamber system of Fig. 1A, showing an annealing method of an embodiment comprising the formation of a partial region of localized control of ambient oxygen using a mixed gas. [Fig. 3A] is a close-up view of the surface of the semiconductor wafer after the introduction of the mixed gas inside the processing chamber, showing how the mixed gas and oxygen are generally uniformly distributed on the surface of the semiconductor wafer before the laser annealing. [Fig. 3B] is a close-up view of a partial region of an annealing position formed in the process of laser annealing and surrounding the surface of the semiconductor wafer, wherein the oxygen concentration of the local region is low due to a decrease in the oxygen content (concentration) of the local region The oxygen concentration in other areas inside the processing chamber.

40‧‧‧Laser beam

50‧‧‧Semiconductor substrate (wafer)

52‧‧‧ upper surface

55‧‧‧Annealed position

70‧‧‧Processing chamber interior (internal)

202‧‧‧ gas, mixed gas

205‧‧‧Oxygen

RG‧‧‧ local area

r _G ‧‧‧ Radius

T _C ‧‧‧ combustion temperature isotherms

Claims (20)

A method of performing laser annealing on a semiconductor wafer having a surface for reducing or avoiding oxidation of the surface, the method comprising: a) disposing the semiconductor wafer inside a processing chamber; b) processing the semiconductor wafer The interior of the chamber is evacuated such that a residual oxygen contained within the processing chamber is at an initial concentration derived from the air retained in the processing chamber in step a); c) in the processing chamber Introducing a mixed gas comprising a hydrogen gas and a buffer gas, and no oxygen is introduced into the processing chamber after step a); and d) directing a laser beam through the interior of the processing chamber to be incident on the An annealing location on the surface of the semiconductor wafer, thereby annealing the surface of the semiconductor wafer and causing a portion of the interior of the processing chamber adjacent to the annealing location and adjacent to the surface of the semiconductor wafer The residual oxygen and the hydrogen in the mixed gas are locally heated, and the residual oxygen in the partial region is combusted with the hydrogen to generate water vapor, so that the residual oxygen in the local region Concentration below the initial concentration of the residual oxygen. The method of claim 1, wherein the mixed gas comprises 5 vol% of hydrogen and 95 vol% of nitrogen. The method according to a request, wherein the local region is defined by a combustion system temperature T _C, the combustion temperature T _C between lines range of 100 deg.] C to 500 deg.] C. The method of claim 1 wherein the processing chamber comprises a microchamber. The method as claimed in claim 1, further comprising: The semiconductor wafer is moved relative to the laser beam such that the annealing position moves relative to the surface of the semiconductor wafer, but the annealing position remains fixed relative to its initial position within the processing chamber. The method of claim 1, wherein the initial concentration is greater than or equal to 50 ppm, and the concentration of the residual oxygen in the localized region is less than or equal to 10 ppm. The method of claim 1, wherein the semiconductor wafer has a melting temperature T _M , the surface of the semiconductor wafer is annealed at an annealing temperature T _A , and T _A <T _M . The method of claim 1, wherein the mixed gas has a partial pressure ranging from 1 mTorr to 1000 Torr. A method of reducing residual oxygen in a localized region around an annealing location when annealing a semiconductor wafer having a surface for reducing or avoiding oxidation of the surface, the method comprising: under vacuum Introducing a processing gas into a mixed gas comprising a hydrogen gas and a buffer gas, the processing chamber comprising the semiconductor wafer and the residual oxygen at an initial concentration, the residual oxygen is derived from the processing chamber before being in a vacuum state The air present in the processing chamber, and no oxygen is introduced into the processing chamber under vacuum; and the laser anneals the surface of the semiconductor wafer, thereby causing the periphery of the annealing location adjacent to the semiconductor crystal The residual oxygen in a local region of the processing chamber of the circle and the hydrogen in the mixed gas are locally heated, and the residual oxygen in the local region is combusted with the hydrogen to generate water vapor, thereby causing water vapor The residual oxygen concentration in the localized region is lower than the initial concentration of the residual oxygen. The method of claim 9, wherein the mixed gas comprises 5 vol% of hydrogen and 95 vol% of nitrogen. The method of the requested item 9, wherein the local region is defined by a combustion system temperature T _C, the combustion temperature T _C between lines range of 100 deg.] C to 500 deg.] C. The method of claim 9 wherein the processing chamber comprises a microchamber. The method of claim 9, further comprising: moving the semiconductor wafer relative to the laser beam to move the annealing position relative to the surface of the semiconductor wafer, but the annealing position is relative to the processing The initial position inside the cavity remains fixed. The method of claim 9, wherein the initial concentration of the oxygen is greater than or equal to 50 ppm, and the concentration of oxygen in the localized region is less than or equal to 10 ppm. The method of claim 9, wherein the semiconductor wafer has a melting temperature T _M , the surface of the semiconductor wafer being annealed at an annealing temperature T _A , and T _A <T _M . A method for performing laser annealing on a semiconductor wafer having a surface for reducing or avoiding oxidation of the surface, the method comprising: disposing the semiconductor wafer inside a processing chamber, wherein the processing chamber is located inside An initial concentration of residual oxygen derived from air originally present in the processing chamber and retained after the processing chamber is evacuated; a mixed gas is introduced into the processing chamber, the mixed gas comprising a hydrogen gas And a buffer gas, and no oxygen is introduced into the processing chamber after being evacuated; and directing a laser beam through the interior of the processing chamber to be incident on an annealing position on the surface of the semiconductor wafer, thereby Annealing the surface of the semiconductor wafer and causing the periphery of the annealing location The residual oxygen in a local region of the interior of the processing chamber adjacent to the surface of the semiconductor wafer and the hydrogen in the mixed gas are locally heated, and the residual oxygen and the hydrogen in the local region Combustion occurs to produce water vapor such that the concentration of oxygen in the localized region is lower than the initial concentration of the residual oxygen. The method of claim 16, wherein the mixed gas has a partial pressure ranging from 1 mTorr to 1000 Torr. The method of claim 17, wherein the initial concentration is greater than or equal to 50 ppm, and the oxygen concentration in the localized region is less than or equal to 10 ppm. The method of claim 16 wherein the processing chamber comprises a microchamber. The method of claim 16, wherein the mixed gas comprises 5 vol% hydrogen and 95 vol% nitrogen.